Commercial installation power amplifiers have features that are built in to them specifically for use in the installation of permanent sound systems. These extra features may include digital signal processing, the ability to run 24 hours a day, a 70 or 100 volt output, among others.
Special attention has gone into the design of installation power amplifiers since it is expected that these power amplifiers will be pushed for long hours and sometimes under very heavy loads.
Since these are not generally moved around much, many companies have not bothered to invest in switching power supplies (the thing that makes some power amplifiers weigh only 10 pounds) so you may find that some of these amplifiers still tip the scales at weights at or above 50 pounds.
In addition, the inputs and outputs are usually Euroblock or terminal strips.